In vitro antiradical and neuroprotective activity of polyphenolic extract from marine algae Padina australis H.

The neuroprotective properties and antioxidant potential of polyphenolic extracts from a brown seaweed Padina australis, were evaluated by the inhibition assay against acetylcholine esterase using indoxyl acetate as the substrate, and by the radical scavenging activity assay against 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and ferrous ion chelating (FIC) activity assay. Methanolic (80%) crude extracts was fractionated by different solvent partitioning, and the assays of each fraction were performed using the microplate reader. The highest total phenolic content (TPC) was observed in n-butanol soluble fraction with a value of 188.75±0.21 mg GAE/g. In addition, the n-butanol soluble fraction showed the highest ferric reducing power (188.34±0.15 mg GAE/g) and the highest ferrous ion chelating ability (76.52±0.12%). The highest free radical scavenging activity against DPPH was found in water soluble fraction with 77.5±1.82% inhibition. However, the βcarotene bleaching activity was found higher with the non-polar solvent, n-hexane extract (58.12±0.58%). A strong positive correlation was found between the total phenolics and antioxidant activities of the fractions. Acetylcholinesterase (AChE) inhibitory properties of all the fractions were assayed where n-butanol soluble fraction was found to have better AChE inhibitory activity (57.94±0.17%) with an IC50 value of 1.54±0.045 mg/ml. The results suggested that the polar fractions possess higher AChE inhibitory and antioxidant activity. It can be concluded that Padina australis possesses an appreciable amount of polyphenols with notable antioxidant and antiAChE properties that could be promisingly used in the treatment of neurodegenerative disorders

In vitro antiradical and neuroprotective activity of polyphenolic extract from marine algae Padina australis H.

The neuroprotective properties and antioxidant potential of polyphenolic extracts from a brown seaweed Padina australis, were evaluated by the inhibition assay against acetylcholine esterase using indoxyl acetate as the substrate, and by the radical scavenging activity assay against 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and ferrous ion chelating (FIC) activity assay. Methanolic (80%) crude extracts was fractionated by different solvent partitioning, and the assays of each fraction were performed using the microplate reader. The highest total phenolic content (TPC) was observed in n-butanol soluble fraction with a value of 188.75±0.21 mg GAE/g. In addition, the n-butanol soluble fraction showed the highest ferric reducing power (188.34±0.15 mg GAE/g) and the highest ferrous ion chelating ability (76.52±0.12%). The highest free radical scavenging activity against DPPH was found in water soluble fraction with 77.5±1.82% inhibition. However, the βcarotene bleaching activity was found higher with the non-polar solvent, n-hexane extract (58.12±0.58%). A strong positive correlation was found between the total phenolics and antioxidant activities of the fractions. Acetylcholinesterase (AChE) inhibitory properties of all the fractions were assayed where n-butanol soluble fraction was found to have better AChE inhibitory activity (57.94±0.17%) with an IC50 value of 1.54±0.045 mg/ml. The results suggested that the polar fractions possess higher AChE inhibitory and antioxidant activity. It can be concluded that Padina australis possesses an appreciable amount of polyphenols with notable antioxidant and antiAChE properties that could be promisingly used in the treatment of neurodegenerative disorders

Study on antioxidant and antidiabetic properties of phloroglucinol from brown macroalgae Padina australis Hauck

Diabetes is a metabolic disorder characterized by high levels of blood glucose. It is caused by the pancreatic insufficiency or by insulin resistance. Marine macroalgae extracts have been established to have strong antidiabetic and antioxidant properties. In the present study, the antidiabetic and antioxidant potential of polyphenolic extract from a brown seaweed Padina australis was evaluated. Methanolic (80:20 % of MeOH: Deionized Water v/v) extract of P. australis was partitioned with five different solvents. The carbolytic enzyme inhibiting functions, radical scavenging activity assay against 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) activity, beta-carotene bleaching properties are evaluated. The antiradical and antidiabetic inhibition assays were statistically significant as the different extracts of P. australis inhibited the enzymes in vitro and in vivo. Among the five different fractions, n-butanol fraction showed significantly higher antiradical and antidiabetic inhibitory activity. The methanolic extract was subjected to TLC and HPLC analysis to identify the bioactive molecules present in the mixture of extract. Further LC-MS analysis of n-butanol 5th fraction revealed the presence of three Phlorotannin compounds namely Phloroglucinol, Eckol, and Phlorofucofuroeckol A. Sephadex LH-20, column chromatography technique, was employed to isolate Phloroglucinol compound for further study. Phloroglucinol isolated and purified from the active fraction was evaluated for antidiabetic effect in Streptozotocin-induced diabetic rats. Among the tested portions, n-butanol fraction had significant α- glucosidase and α-amylase inhibitory activity with IC50 value 2.06 ± 0.14 and 2.90 ± 0.08 mg/mL respectively, as compared to Acarbose. Acute toxicity of the isolated pure compound at 20 and 40 mg/kg doses in Swiss Albino mice was found to have potent antidiabetic activity by ameliorating glucose, lipids, and antioxidant parameters. The toxicology studies also showed that the pure compound Phloroglucinol did not have any toxic effects in the internal organs; biochemical and hematological parameters. These findings suggest that the dietary use of Padina australis and the isolated compound Phloroglucinol can be used as medicine for the treatment of diabetes. This work could help to develop new oral antihyperglycemic agent in the management of diabetes mellitus

Metabolic responses of tea (Camellia sp.) to exogenous application of ascorbic acid

Effects of exogenous application of ascorbic acid on physiological and metabolic changes in tea were investigated in the present study. The highest improvement in yield was evident in response to regular application (a day after every harvest) of ascorbic acid at 600 ppm followed by 400 ppm. Foliar application of ascorbic acid (600 ppm) at regular intervals enhanced chlorophyll a and b contents besides a significant increase in total polyphenols and catechins when compared to the untreated control. Exogenous application of ascorbic acid at alternate harvesting rounds increased the activity of polyphenol oxidase whereas ascorbate peroxidase remained unchanged. An increase in phenylalanine ammonia lyase activity was noticed with foliar application of ascorbic acid irrespective of its concentrations. Theaflavins and thearubigins of made tea showed an increase when ascorbic acid was applied with 400 and 600 ppm at alternate intervals. The scores of brewed tea liquor characteristics, viz. infusion, color, strength, and briskness were higher even at the lower concentration of ascorbic acid treatment. Results suggest that foliar application of ascorbic acid (400 ppm) proved to be a useful measure to improve the yield, physiological attributes, and antioxidant properties of tea

New Insights into Seaweed Polyphenols on Glucose Homeostasis

Context: Polyphenol-rich marine macroalgae are gaining dietary importance due to their influence over diabetes mellitus and the role as a vital source of high-value nutraceuticals. Their assorted beneficial effects on human health include competitive inhibition of digestive enzymes, varying the activity of hepatic glucose-metabolizing enzymes, lowering the plasma glucose levels, and lipid peroxidation, delaying the aging process. Objective: In this paper, we review the health beneficial effects of polyphenols and phlorotannins from brown seaweeds with special emphasis on their inhibitory effects on carbohydrate-metabolizing enzymes. Methods: A survey of literature from databases such as Sciencedirect, Scopus, Pubmed, Springerlink, and Google Scholar from the year 1973 to 2013 was done to bring together the information relating to drug discovery from brown seaweeds as a source for diabetes treatment. Results: Over the past two decades, 20 different bioactive polyphenols/phlorotannins have been isolated and studied from 10 different brown algae. Discussion of the positive effect on the inhibition of enzymes metabolizing carbohydrates in both in vitro and in vivo experiments are included. Conclusion: Despite the recent advancements in isolating bioactive compounds from seaweeds with potential health benefit or pharmaceutical behavior, studies on the polyphenol effectiveness on glucose homeostasis in human beings are very few in response to their functional characterization. Added research in this area is required to confirm the close connection of polyphenol rich seaweed-based diet consumption with glucose homeostasis and the exciting possibility of prescribing polyphenols to treat the diabetes pandemic